Abstract
The purpose of this study was to study how temperature variation affects the tolerance of phosphorus accumulating organisms (PAOs) in a toxic environment. To exclude the interference of glycogen accumulating organisms (GAOs), shock loading experiments were conducted to study the effect of Cu(II) toxicity on the metabolisms of PAOs in 10, 20, and 30 °C conditions. The experimental data showed that the temperature effects on aerobic phosphorus uptake, PHA degradation, and glycogen synthesis were remarkable in the presence of Cu(II). Nevertheless, insignificant effects on anaerobic phosphorus release and PHA synthesis were found. The largest inhibition of PAO metabolism occurred in the low temperature case (10 °C). This study also experimentally demonstrated the loss of PAO metabolic ability in the subsequent aerobic stage, after the anaerobic stage. The presence of Cu(II) toxicity mainly resulted from the inhibition of biochemical reactions in the aerobic stage, and it was irrelevant to the inhibition of previous anaerobic metabolisms.
Highlights
Enhanced biological phosphorus removal (EBPR) is considered an efficient process for removing phosphorus from wastewater
Substrate type has been identified as an important factor affecting the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), which are usually dominant in a deteriorated EBPR system [3]
Both the specific phosphate release rate (SPRR) and specific substrate uptake rate (SSUR) of PAOs in the anaerobic stage increased with an increasing temperature from 10 to 30 ◦ C
Summary
Enhanced biological phosphorus removal (EBPR) is considered an efficient process for removing phosphorus from wastewater. Microorganisms are responsible for phosphate removal, and the mechanisms by which they accumulate phosphorus are complex and not well-understood [1]. This process remains operationally unstable in many systems, and it is difficult to reliably meet low effluent limits [2]. Past research has shown high inhibition of heavy metal ions to biological carbon, nitrogen, and phosphate removal in EBPR [4,5,6,7,8]. A related study was conducted by Tsai et al [6] They tried to chronically and stepwise add heavy metal Cd(II) ions into an A2 O pilot plant to examine the toxic effects on organism behaviors. The results showed that an addition of 2 mgCd L−1 started to affect the efficiency
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